Feed roller construction and drive



July 7, 1970 o. 5. SMITH FEED ROLLER CONSTRUCTION AND DRIVE 2 Sheets-Sheet 1 Original Filed Oct. 2, 1967 5 INVENTOR. ORBERT 5. 5mm

ATTORNEY July 7, 1970 o. 5. SMITH FEED ROLLER CONSTRUCTION AND DRIVE 2 Sheets-Sheet 2 Original Filed Oct. 2, 1967 United States Lite 3,5l9,ll7 Patented July 7, 1970 US. Cl. 197138 9 Claims ABSTRACT OF THE DISCLOSURE The rear feed roll for the paper of a typewriter or adding machine is restrained in one direction by a oneway clutch for imposing a drag on the paper as it moves toward the printing area. Alternatively, the front feed roll is overdriven through a one-way clutch for drawing the paper ahead of the platen as it moves out of the work area. Preferably both the front and rear feed rolls are similarly equipped, but oppositely oriented for pulling the paper taut for both directions of rotation of the cylindrical platen. The slippage may occur between the rollers and the paper, or slip clutches may be included.

This application is a continuation of patent application Ser. No. 672,132 filed Oct. 2, 1967, now abandoned.

BACKGROUND OF THE INVENTION Field of the invention The present invention relates to feed rolls for the paper, or work sheet, on a typewriter, adding machine, or the like.

Description of the prior art Feed rolls have usually turned free on their supports, as for example, in US. Pat. No. 2,163,944, but since any slight friction restraint acted equally in both directions, it often caused wrinkling of the paper, if the Work consisted of several sheets, or if the platen was turned backward. Feed rolls have been overdriven from the platen, as in US. Pat. No. 2,274,834, where the upper, or output, feed rolls tend to draw the paper faster than the platen does, but when the platen is reversed, the overdriven rolls produce slack in the paper.

Summary of the invention The feed rolls have one-way clutches, each oriented to lock on its support when turned thereon in the direction that carries the paper from it toward the print area. The support may be nonrotative so that for both forward and backward rotation of the platen, the clutch and roller imposes a drag on the paper as it moves toward the work space, or the support may be driven at a greater speed than the platen for overdriving the paper as it leaves the work area. Either action reduces slack and holds the paper taut for every rotation of the platen, either backward or forward. A slip clutch may be included.

BRIEF DESCRIPTION OF THE DRAWINGS These and other objects and advantages of the invention will be apparent from the following description of specific embodiments, taken in connection with the accompanying drawing, wherein:

FIG. 1 is a fragmentary left elevation of a typewriter, partly in section, showing the platen, feed rollers and associated parts embodying my invention;

FIG. 2 is a perspective view of part of the apparatus of FIG. 1;

FIG. 3 is an enlarged, perspective, cut-away view of a feed roller; and

FIG. 4 is a perspective view of a second embodiment of my invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The machine of the specific embodiment of FIGS. 1 and 2 includes a rotatable platen 10, front feed, or pressure, rollers 12, rear feed, or pressure, rollers 14, a type wheel 16 and a type hammer 18. Means for driving and rotating the platen 10 include a ratchet 6 and pawl 7 of known construction for driving it in the forward direction indicated by arrow 8, and include also a manual knob 9 for rotation in both directions. A strip of paper 20, or work sheet, enters the machine at 22, passes down between the platen 10 and rear feed rollers 14, forward under the platen 10 at 19, up at the front of the platen 10 through a printing area, or work area 21, behind the type wheel 16, up between the platen 10 and the front feed rollers 12, and out of the machine at 24. The front feed rollers 12 are carried on a shaft, support, or bail rod 26, which is fixed and nonrotatable in bail arms 28, and are urged by a spring 30 into a firm pressure engagement with the platen 10.

The rear feed rollers 14 are supported on a shaft, or support 32 which is nonrotatably carried by leaf springs 34. Cams 36 carried on a common shaft 38, are shown in a position in which they hold the rollers 14 firmly against the platen 10, but are rotatable for releasing the rollers 14. Thus, each of the feed rollers 12 and 14 is spaced from the work area 21 along the direction of motion of the work sheet 20 between such roller and the work area 21.

Each of the rollers 12 and 14 is equipped with both a one-way clutch 47, FIG. 3, and slip clutch 43. The one-Way clutches 47 are oriented to roll free on the nonrotatable shafts 26 and 32 when the paper 20 exits at the particular roller 12 or 14, and to oppose the rotation of the roller 12 or 14 and thereby impose a drag on the paper 20 when the paper 20 enters at that roller 12 or 14. These directions, in which the feed rollers 12 and 14 roll free on their support shafts 26 and 32, are indicated by arrows 13 and 15.

One of the feed rollers 12 and its cltuches 43 and 47 is shown in an enlarged, perspective, cutaway view in FIG. 3. The shaft 26 has a circumferential groove 40 which receives a friction element 42, such as a rubber O-ring 42 as shown, or a metal spring. A bushing 44 has a groove 45 which fits over the O-ring 42 with a slight pressure so that the bushing 44 is rotatable about the shaft 26, but is frictionally restrained. These parts 26, 42 and 44, together constitute the slip clutch 43. It slips at a torque less than that required for sliding the roller 12 on the paper 20.

The bushing 44 is the central part of the one-way clutch 47 which also includes a camming race 46 having tapered recesses 49 containing rollers 48. A light metal cover 50 encloses the one-way clutch 47 and retains the rollers 48 in place. An outer rubber tire 52, for providing a good traction on the paper completes the feed roller 12.

Referring to FIG. 3, when the tire 52 and camming race 46 rotate in the direction of the arrow 13, counterclockwise in FIG. 3, the rollers 48 lag behind the motion of the race 46, move to the wide parts of the tapered recesses 49, and let race 46 and tire 52 turn free on the bushing 44. When the race 46- is rotated in the opposite direction, that is, against the arrow 13 and clockwise in FIG. 3, the rollers 48 again lag behind the motion of the race 46, and this time they move to the narrow portions of the tapered recesses 49 where they jam between the race 46 and bushing 44. This action locks the race 46 and bushing 44 together so that the roller 12 can rotate only by slippage between the O-ring 42 and one or the other of the bushing 44 and shaft 26.

3 The apparatus of FIGS. 1 and 2 removes slack from the paper or work sheet 20 by imposing a drag at the entrance feed rollers 12 or 14. When the platen is rotated in its forward direction indicated by arrow 8, that is, in the direction in which the paper progresses through the machine in the normal operation of typing on it, clockwise in FIG. 1, the roller 14 is the entrance roller and roller 12 is the exit roller. When the platen 10 is turned in the opposite direction, that is, backward, counter-clockwise in FIG. 1, roller 12 becomes the entrance roller and roller 14 the exit roller. As indicated by the arrows 13 and 15, each of the rollers 12 and 14 in FIG. 1 rolls free only in the direction in which it serves as the exit roller, that is, when the side of the roller 12 or 14 toward the platen 10 moves away from the work area 21. In each of these rollers 12 and 14, when it serves as an entrance roller, so that its side toward the platen 10 moves toward the work area 21, its one-way clutch 47 engages so that its friction clutch 43 imposes a drag on the paper 20. This drag causes the paper 20 to slip on the platen 10 at that entrance roller 12 or 14 and to progress more slowly than the rotation of the platen 10, so that slack is rapidly removed from the paper 20, and so that the paper 20 is continually held taut between the two rollers 12 and 14, and particularly at the work space 21 opposite the type wheel 16 and printing hammer 18.

As seen in FIG. 2, I employ several front feed rollers 12 on the bail shaft 26, and similarly, several rear feed rollers .14 on shaft 32. Each of these rollers 12, 14 slips, locks and runs free, independently of the others. This independent action of the roller 12, 14 is particularly useful for reducing conditions of uneven slack as when the paper 20 is skewed so that more slack appears at one edge than at the other.

It is feasible to eliminate the slip clutch 43 as by mounting the bushing 44 nonrotatably on the bail shaft 26, and letting the slippage occur between the roller 12 and the paper 20, However, such slippage against the paper 20 tends to smear the printing, provides an unpredictable and variable frictional force, and lets slippage also occur in an axial direction. Accordingly, I prefer to provide individual slip clutches 43 for the rollers 12 and 14 as described, each arranged to slip before its roller 12 or 14 slides on the paper 20.

The modification of FIG. 4 differs from that of FIGS. 1 and 2 in that the shafts 27 and 33 which support the feed, or pressure, rollers 12 and 14 are driven from the platen 10 and are geared up for making the rollers 12 and 14 overdrive. In FIG. 4, a gear 60 is fixed to the shaft 11 of the platen 10, and pinions 62 and 64, driven by the gear 60, are fixed to the shafts 27 and 33 which support the rollers 12 and 14. The numbers of teeth on the gear 60 and on pinions 62 and 64 are such that they drive the surface of the rollers 12 and 14 faster than the surface movement of the platen 10. Because of the action of the one-way clutches 47, this overdrive occurs only at the exit roller, i.e., the roller 12 or 14 at which the paper 20 is leaving the platen 10.

The one-Way clutches 47 are oriented the same in FIG. 4 as in FIGS. 1 and 2. The fact that in FIG. 4 they exert a pull at the exit rollers rather than a drag at the input rollers, results from overdriving the supporting shafts 27 and 33 in FIG. 4, for reversing the relative motion between the inner parts 44 and outer parts 46 of the one-way clutches 47. This result can be seen from an examination of the action of rollers 48 in FIG. 3.

Arrow 13 indicates the exit direction of roller 12, that is, the direction in which feed roller 12 rolls free on bushing 44, when bushing 44 is stationary as in FIG. 1. But, since it is the relative motion between race 46 and bushing 44 that controls rollers 48, the clutch 47 is free also when bushing 44 turns clockwise (against arrow 13) inside of race 46, and also when both race 46 and bushing 4 44 turn clockwise (entrance direction), but bushing 44 turns faster as in FIG. 4.

Similarly, with bushing 44 stationary, as in FIGS. 1 and 2, if race 46 turns clockwise, against arrow 13, that being the entrance direction, the rollers 48 lag behind and jam in the narrow ends of the tapered recesses 49 to engage the clutch 47. Also, if the bushing 44 is driven faster than race 46 as in FIG. 4, and driven counterclockwise, with the arrow 13, that being the exit direction, the bushing 44 runs counter-clockwise ahead of race 46 and carries the rollers 48 into the narrow end of the recesses 49 for engaging the clutch 47.

S0, in FIG. 4, when platen 10 turns forward, or clockwise, the gears 60 and 62 overdrive bail shaft 27 and rollers 12, counter-clockwise, to pull the paper 20 ahead of the motion of the platen 10. This is the direction of rotation when the paper 20 exits at the roller 12. At the same time in FIG. 4, the gear 64 drives the shaft 33 counterclockwise faster than the platen 10 tends to turn the roller 14, and consequently it causes the one-way clutch 47 in roller 14 to disengage. When the platen 10 is rotated backward, counter-clockwise, front rollers 12 in FIG. 4 run free and rear rollers 14 pull the paper 20 ahead of the platen 10. Thus, in FIG. 4, the entrance rollers run free, but the exit rollers are overdriven for pulling the paper 20 ahead of the platen motion for reducing slack in the paper 20 and for holding it taut.

As in the construction of FIGS. 1 and 2, I prefer in the construction of FIG. 4, to use several rollers 12 and 14 on each shaft 27 and 33, and to provide them with independent one-way clutches 47 and slip clutches 43.

In FIG. 4, when the bail shaft 27 is lifted for the insertion of a new sheet of paper 20, the pinion 62 will be lifted from the gear 60, but will easily slip into mesh when it is again put in operating position. The gear 64 may or may not be disengaged from the gear 60 when the rollers 14 are withdrawn from the platen 10.

The one-way clutches 47 of the construction of the present invention are symmetrical with respect to the printing area 21. In FIGS. 1 and 2, for each direction of rotation of the platen 10, the entrance roller 12 or 14 engages its one-way clutch 47 and imposes a drag on the paper 20 for holding it taut. Similarly, in FIG. 4, for each direction of rotation of the platen 10, the exit roller 12 or 14 is immediately overdriven for pulling the paper 20 taut. Thus, the operator may freely rotate the platen 10 backward for making corrections, or forward for making the work easier to read, and every such backward or forward motion tends to reduce slack and pull the paper 20 taut. The taut condition of the paper 20 provides clear readable printing and neat alignment of the work, eliminates any tendency to press wrinkles and folds into the paper, and reduces the noise of operation.

In FIG. 3, tire 52, cover 50 and the main body of race 46 constitute a feed, or pressure, roller 12. The cam surfaces, or tapered recesses 49, of race 46, the rollers 48, and the main body of bushing 44 constitute a one-way clutch 47. The bushing 44, friction ring 42, and grooved shaft 26 constitute a slip clutch 43. The shaft, or bail rod, 26 is a support for the torque exerted on the roller 12 by the slip clutch 43 and by the one-way clutch 47. The shaft 26 also provides the mounting for the roller 12, and transmits to it the force of springs 30 for gripping the paper. The slip clutch 43 and the one-way clutch 47 are in a connection between the feed roller 12 and the supporting bail 26, and they are in series in that connection, for coupling the feed roll 12 to its support bail 26. In FIG. 4, the shafts, or bails, 27 and 33, are driven by gear 60 and are also restrained thereby against free rotation with their rollers 12 and 14. In FIGS. 1 and 2 the shafts, or bails, 26 and 32 are nonrotatably secured in arms 28 and springs 34,

and are thereby restrained against free rotation with their rollers 12 and 14.

I claim:

1. In combination in a work sheet holder, for a typewriter or the like, having (a) a platen movable in a forward and a reverse direction for carrying a work sheet, (b) first and second rotatable pressure rollers for holding said work sheet against said platen for enabling said platen to move said work sheet, (c) means defining a work area having an entrance and an exit portion each of said pressure rollers being spaced from said work area along the direction of movement of said platen and said work sheet, (d) means coupled to said platen for moving said platen in said forward and said reverse directions, (e) a first fixed nonrotatable support for said first pressure roller, (f) first restraining means coupled to said first support for preventing displacement of said first support along the direction of motion of the surface of said platen and for opposing free rotation of said first support with said first pressure roller, (g) a second support for said second pressure roller, and (h) means urging said supports toward said platen for gripping a work sheet between said rollers and said platen, the improvement which comprises (j) a means for reducing slack in the portion of said work sheet positioned in said work area, said slack reducing means comprising first one-way clutch means coupled to said first pressure roller for opposing rotation thereof in a first direction to provide a drag force on said work sheet and for causing substantially free rotation of said first pressure roller in a second direction, and a first slip clutch coupled to said first one-way clutch means for causing said first pressure roller to rotate in said first direction whenever said drag force exceeds a predetermined value.

2. The combination of claim 1 wherein said first pressure roller, said first one-way clutch means, and said first slip clutch are positioned adjacent said entrance portion of said work area and said second pressure roller is positioned adjacent said exit portion of said work area so that said drag force is applied as said work sheet is moved through said Work area from said entrance portion through said exit portion.

3. The combination of claim 1 wherein said second support comprises a fixed nonrotatable support and further including a second restraining means coupled to said second support for preventing displacement of said second support along the direction of motion of the surface of said platen and for opposing free rotation of said second support with said second pressure roller, and wherein said slack reducing means further includes second one-way clutch means coupled to said second pressure roller for opposing rotation thereof in said second direction to provide a drag force on said work sheet and for causing substantially free rotation of said second pressure roller in said first direction.

4. The combination of claim 3 wherein said slack reducing means further includes a second slip clutch coupled to said second one-way clutch means for causing said second pressure roller to rotate in said second direction whenever said drag force exceeds a predetermined value.

5. The combination of claim 4 wherein said first roller, said first one-way clutch means and said first slip clutch are positioned adjacent said entrance portion of said work area and said second roller, said second one-way clutch means and said second slip clutch are positioned adjacent said exit portion of said work area so that a drag force is applied to said work sheet as said work sheet is moved by said platen through said work area in both said reverse and said forward directions.

6. In combination in a work sheet holder, for a typewriter or the like, having (a) a platen movable in a forward and a reverse direction for carrying a work sheet, (b) first and second rotatable pressure rollers for holding said work sheet against said platen for enabling said platen to move said work sheet, (0) means defining a work area having an entrance portion and an exit portion, each of said pressure rollers being spaced from said work area along the direction of movement of said platen and work sheet, (d) means coupled to said platen for moving said platen in said forward and said reverse directions, (e) a first support for said first pressure roller, (f) first restraining means coupled to said first support for preventing displacement of said first support along the direction of motion of the surface of said platen and for opposing free rotation of said first support with said first pressure roller, (g) a second support for said second pressure roller, and (h) means urging said supports toward said platen for gripping a work sheet between said rollers and platen, the improvement which comprises (j) a means for reducing slack in the portion of said work sheet positioned in said work area, said slack reducing means comprising first overdrive means coupled to said first support and responsive to movement by said platen for driving said first pressure roller in a first direction at a peripheral speed greater than the peripheral speed of said platen, first one-way clutch means coupled to said first pressure roller for coupling rotary motion in said first direction between said first support and said first pressure roller and for causing substantially free rotation of said first pressure roller in a second direction, and a first slip clutch coupled to said first one-way clutch means for reducing the peripheral speed of said first pressure roller in said first direction whenever said slack is substantially eliminated.

7. The combination of claim 6 wherein said first pressure roller, said first one-way clutch means, and said first slip clutch are positioned adjacent said exit portion of said work area and said second pressure roller is positioned adjacent said entrance portion of said work area so that said slack is reduced as said work sheet is moved through said work area from said entrance portion to said exit portion.

8. The combination of claim 6 wherein said slack reducing means further includes a second overdrive means coupled to said second support and responsive to movement by said platen for driving said second pressure roller in said second direction at a peripheral speed greater than the peripheral speed of said platen, second one-way clutch means coupled to said second pressure roller for coupling rotary motion in said second direction between said second support and said second pressure roller and for causing substantially free rotation of said second pressure roller in said first direction, and a second slip clutch coupled tosaid second one-way clutch means for reducing the peripheral speed of said second pressure roller in said second direction Whenever said slack is substantially eliminated.

9. The combination of claim 8 wherein said first pressure roller, said first one-way clutch means and said first slip clutch are positioned adjacent said exit portion of said work area, and said second pressure roller, said second one-way clutch means and said second slip clutch are positioned adjacent said entrance portion of said work area so that said slack is reduced as said work sheet is moved through said work area in both said forward and said reverse directions.

References Cited UNITED STATES PATENTS 991,706 5/1911 Dennis. 1,105,853 8/1914 Shiek. 1,118,101 11/1914 Brown. 1,145,017 7/1915 Hess. 1,296,191 3/1919 Ireland. 1,900,102 3/1933 Going. 2,163,944 6/ 1939 Helmond. 2,274,834 3/ 1942 Ira. 2,356,842 8/1944 Helmond. 2,772,765 12/ 1956 Maroth. 2,787,357 4/1957 Segui.

ERNEST T. WRIGHT, JR., Primary Examiner US. Cl. X.R. 197-127 

